* [PATCH] Place ENTRY_POINT in .text.startup section [BZ #28153]
@ 2021-07-31 4:22 H.J. Lu
2021-07-31 5:40 ` Andreas Schwab
0 siblings, 1 reply; 3+ messages in thread
From: H.J. Lu @ 2021-07-31 4:22 UTC (permalink / raw)
To: libc-alpha
Glibc assumes that ENTRY_POINT is the lowest address for which we need
to keep profiling records. Since GCC 4.6, the main function is placed
in .text.startup section. Because ENTRY_POINT in gcrt1.o, which is read
in by the linker first, is not placed in .text.startup section, linker
may place the main function below ENTRY_POINT which leaves the main
function out of profiling records.
Place ENTRY_POINT in .text.startup section fixes [BZ #28153].
Tested on Linux/x86-64 and Linux/i686 as well as with build-many-glibcs.py.
---
gmon/tst-gmon-gprof.sh | 2 ++
gmon/tst-gmon-static-gprof.sh | 2 ++
sysdeps/aarch64/start.S | 2 +-
sysdeps/alpha/start.S | 2 +-
sysdeps/arc/start.S | 1 +
sysdeps/arm/start.S | 2 +-
sysdeps/csky/abiv2/start.S | 2 +-
sysdeps/hppa/start.S | 2 +-
sysdeps/i386/start.S | 1 +
sysdeps/ia64/start.S | 1 +
sysdeps/m68k/start.S | 2 +-
sysdeps/microblaze/start.S | 2 +-
sysdeps/mips/start.S | 2 +-
sysdeps/nios2/start.S | 2 +-
sysdeps/powerpc/powerpc32/start.S | 2 +-
sysdeps/powerpc/powerpc64/start.S | 2 +-
sysdeps/riscv/start.S | 1 +
sysdeps/s390/s390-32/start.S | 2 +-
sysdeps/s390/s390-64/start.S | 2 +-
sysdeps/sh/start.S | 2 +-
sysdeps/sparc/sparc32/start.S | 2 +-
sysdeps/sparc/sparc64/start.S | 2 +-
sysdeps/x86_64/start.S | 1 +
23 files changed, 25 insertions(+), 16 deletions(-)
diff --git a/gmon/tst-gmon-gprof.sh b/gmon/tst-gmon-gprof.sh
index 9d371582b9..dc0be02110 100644
--- a/gmon/tst-gmon-gprof.sh
+++ b/gmon/tst-gmon-gprof.sh
@@ -39,12 +39,14 @@ trap cleanup 0
cat > "$expected" <<EOF
f1 2000
f2 1000
+f3 1
EOF
# Special version for powerpc with function descriptors.
cat > "$expected_dot" <<EOF
.f1 2000
.f2 1000
+.f3 1
EOF
"$GPROF" -C "$program" "$data" \
diff --git a/gmon/tst-gmon-static-gprof.sh b/gmon/tst-gmon-static-gprof.sh
index 79218df967..4cc99c80d0 100644
--- a/gmon/tst-gmon-static-gprof.sh
+++ b/gmon/tst-gmon-static-gprof.sh
@@ -39,6 +39,7 @@ trap cleanup 0
cat > "$expected" <<EOF
f1 2000
f2 1000
+f3 1
main 1
EOF
@@ -46,6 +47,7 @@ EOF
cat > "$expected_dot" <<EOF
.f1 2000
.f2 1000
+.f3 1
.main 1
EOF
diff --git a/sysdeps/aarch64/start.S b/sysdeps/aarch64/start.S
index 417da8802b..4d982b6bd9 100644
--- a/sysdeps/aarch64/start.S
+++ b/sysdeps/aarch64/start.S
@@ -42,7 +42,7 @@
NULL
*/
- .text
+ .section .text.startup,"ax",%progbits
ENTRY(_start)
/* Create an initial frame with 0 LR and FP */
cfi_undefined (x30)
diff --git a/sysdeps/alpha/start.S b/sysdeps/alpha/start.S
index 65dcd4d392..0fb765c3f1 100644
--- a/sysdeps/alpha/start.S
+++ b/sysdeps/alpha/start.S
@@ -36,7 +36,7 @@
#include <sysdep.h>
- .text
+ .section .text.startup,"ax",%progbits
.align 3
.globl _start
.ent _start, 0
diff --git a/sysdeps/arc/start.S b/sysdeps/arc/start.S
index 5302a57cab..33403535d4 100644
--- a/sysdeps/arc/start.S
+++ b/sysdeps/arc/start.S
@@ -33,6 +33,7 @@
env[0...N] environment variables (pointers)
NULL. */
+ .section .text.startup,"ax",%progbits
ENTRY (ENTRY_POINT)
/* Needed to make gdb backtraces stop here. */
diff --git a/sysdeps/arm/start.S b/sysdeps/arm/start.S
index 9b56bc0cca..756046dd9a 100644
--- a/sysdeps/arm/start.S
+++ b/sysdeps/arm/start.S
@@ -69,7 +69,7 @@
.syntax unified
#endif
- .text
+ .section .text.startup,"ax",%progbits
.globl _start
.type _start,#function
_start:
diff --git a/sysdeps/csky/abiv2/start.S b/sysdeps/csky/abiv2/start.S
index a565cfa87b..f2b0e74eb6 100644
--- a/sysdeps/csky/abiv2/start.S
+++ b/sysdeps/csky/abiv2/start.S
@@ -41,7 +41,7 @@
#include <sysdep.h>
- .text
+ .section .text.startup,"ax",%progbits
.globl _start;
.type _start,@function;
.align 4;
diff --git a/sysdeps/hppa/start.S b/sysdeps/hppa/start.S
index 4a1877f8e8..86a21082e8 100644
--- a/sysdeps/hppa/start.S
+++ b/sysdeps/hppa/start.S
@@ -51,7 +51,7 @@
.Lp__libc_start_main:
.word P%__libc_start_main
- .text
+ .section .text.startup,"ax",%progbits
.align 4
.globl _start
.export _start, ENTRY
diff --git a/sysdeps/i386/start.S b/sysdeps/i386/start.S
index 5296b27e65..16767de443 100644
--- a/sysdeps/i386/start.S
+++ b/sysdeps/i386/start.S
@@ -54,6 +54,7 @@
#include <sysdep.h>
+ .section .text.startup,"ax",%progbits
ENTRY (_start)
/* Clearing frame pointer is insufficient, use CFI. */
cfi_undefined (eip)
diff --git a/sysdeps/ia64/start.S b/sysdeps/ia64/start.S
index b28f8cb429..e2b11f42d6 100644
--- a/sysdeps/ia64/start.S
+++ b/sysdeps/ia64/start.S
@@ -48,6 +48,7 @@
* out6: stack_end
*/
+ .section .text.startup,"ax",%progbits
.align 32
.global _start
diff --git a/sysdeps/m68k/start.S b/sysdeps/m68k/start.S
index 98da4db9f3..b2a7f171a5 100644
--- a/sysdeps/m68k/start.S
+++ b/sysdeps/m68k/start.S
@@ -54,7 +54,7 @@
#include <sysdep.h>
- .text
+ .section .text.startup,"ax",%progbits
.globl _start
.type _start,@function
_start:
diff --git a/sysdeps/microblaze/start.S b/sysdeps/microblaze/start.S
index 6589bd4dc7..66c8d8a18d 100644
--- a/sysdeps/microblaze/start.S
+++ b/sysdeps/microblaze/start.S
@@ -33,7 +33,7 @@
License along with the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
- .text
+ .section .text.startup,"ax",%progbits
.globl _start
.type _start,@function
_start:
diff --git a/sysdeps/mips/start.S b/sysdeps/mips/start.S
index 4ec42a2a7f..de0e95a9b8 100644
--- a/sysdeps/mips/start.S
+++ b/sysdeps/mips/start.S
@@ -71,7 +71,7 @@
void (*rtld_fini) (void), void *stack_end)
*/
- .text
+ .section .text.startup,"ax",%progbits
.globl ENTRY_POINT
.type ENTRY_POINT,@function
#ifndef __mips16
diff --git a/sysdeps/nios2/start.S b/sysdeps/nios2/start.S
index 7c9696977f..bb03937d6e 100644
--- a/sysdeps/nios2/start.S
+++ b/sysdeps/nios2/start.S
@@ -65,7 +65,7 @@
value, terminated by an AT_NULL tag.
*/
- .text
+ .section .text.startup,"ax",%progbits
.globl _start
.type _start,%function
_start:
diff --git a/sysdeps/powerpc/powerpc32/start.S b/sysdeps/powerpc/powerpc32/start.S
index 39ce1a18ff..5671d5d7a8 100644
--- a/sysdeps/powerpc/powerpc32/start.S
+++ b/sysdeps/powerpc/powerpc32/start.S
@@ -56,7 +56,7 @@ L(start_addresses):
.long 0 /* Used to be fini. */
ASM_SIZE_DIRECTIVE(L(start_addresses))
- .section ".text"
+ .section .text.startup,"ax",%progbits
ENTRY(_start)
/* Save the stack pointer, in case we're statically linked under Linux. */
mr r9,r1
diff --git a/sysdeps/powerpc/powerpc64/start.S b/sysdeps/powerpc/powerpc64/start.S
index 71c0c67926..e9b6a434f3 100644
--- a/sysdeps/powerpc/powerpc64/start.S
+++ b/sysdeps/powerpc/powerpc64/start.S
@@ -61,7 +61,7 @@ L(start_addresses):
.section ".toc","aw"
.L01:
.tc L(start_addresses)[TC],L(start_addresses)
- .section ".text"
+ .section .text.startup,"ax",%progbits
ENTRY (_start)
/* Save the stack pointer, in case we're statically linked under Linux. */
mr r9,r1
diff --git a/sysdeps/riscv/start.S b/sysdeps/riscv/start.S
index 806f6aacd6..8bbf77d9dd 100644
--- a/sysdeps/riscv/start.S
+++ b/sysdeps/riscv/start.S
@@ -42,6 +42,7 @@
a0 contains the address of a function to be passed to atexit.
__libc_start_main wants this in a5. */
+ .section .text.startup,"ax",%progbits
ENTRY (ENTRY_POINT)
/* Terminate call stack by noting ra is undefined. Use a dummy
.cfi_label to force starting the FDE. */
diff --git a/sysdeps/s390/s390-32/start.S b/sysdeps/s390/s390-32/start.S
index b6cfa4caf3..a418b7f1c6 100644
--- a/sysdeps/s390/s390-32/start.S
+++ b/sysdeps/s390/s390-32/start.S
@@ -55,7 +55,7 @@
NULL
*/
- .text
+ .section .text.startup,"ax",%progbits
.globl _start
.type _start,@function
_start:
diff --git a/sysdeps/s390/s390-64/start.S b/sysdeps/s390/s390-64/start.S
index 4e6526308a..2bc7f89e6a 100644
--- a/sysdeps/s390/s390-64/start.S
+++ b/sysdeps/s390/s390-64/start.S
@@ -55,7 +55,7 @@
NULL
*/
- .text
+ .section .text.startup,"ax",%progbits
.globl _start
.type _start,@function
_start:
diff --git a/sysdeps/sh/start.S b/sysdeps/sh/start.S
index 606ee59222..4beaf43f81 100644
--- a/sysdeps/sh/start.S
+++ b/sysdeps/sh/start.S
@@ -57,7 +57,7 @@
NULL
*/
- .text
+ .section .text.startup,"ax",%progbits
.globl _start
.type _start,@function
_start:
diff --git a/sysdeps/sparc/sparc32/start.S b/sysdeps/sparc/sparc32/start.S
index 00bf898fb9..073596d815 100644
--- a/sysdeps/sparc/sparc32/start.S
+++ b/sysdeps/sparc/sparc32/start.S
@@ -37,7 +37,7 @@
#include <sysdep.h>
- .section ".text"
+ .section .text.startup,"ax",%progbits
.align 4
.global _start
.type _start,#function
diff --git a/sysdeps/sparc/sparc64/start.S b/sysdeps/sparc/sparc64/start.S
index 8520717eba..ad65517ef8 100644
--- a/sysdeps/sparc/sparc64/start.S
+++ b/sysdeps/sparc/sparc64/start.S
@@ -37,7 +37,7 @@
#include <sysdep.h>
- .section ".text"
+ .section .text.startup,"ax",%progbits
.align 4
.global _start
.type _start,#function
diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S
index 1b3e36826b..ff5d1d2af4 100644
--- a/sysdeps/x86_64/start.S
+++ b/sysdeps/x86_64/start.S
@@ -55,6 +55,7 @@
#include <sysdep.h>
+ .section .text.startup,"ax",%progbits
ENTRY (_start)
/* Clearing frame pointer is insufficient, use CFI. */
cfi_undefined (rip)
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Place ENTRY_POINT in .text.startup section [BZ #28153]
2021-07-31 4:22 [PATCH] Place ENTRY_POINT in .text.startup section [BZ #28153] H.J. Lu
@ 2021-07-31 5:40 ` Andreas Schwab
2021-07-31 12:42 ` H.J. Lu
0 siblings, 1 reply; 3+ messages in thread
From: Andreas Schwab @ 2021-07-31 5:40 UTC (permalink / raw)
To: H.J. Lu via Libc-alpha
On Jul 30 2021, H.J. Lu via Libc-alpha wrote:
> Since GCC 4.6, the main function is placed in .text.startup section.
Not generally.
> Place ENTRY_POINT in .text.startup section fixes [BZ #28153].
The linker places .text.unlikely and .text.exit before .text.startup.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Place ENTRY_POINT in .text.startup section [BZ #28153]
2021-07-31 5:40 ` Andreas Schwab
@ 2021-07-31 12:42 ` H.J. Lu
0 siblings, 0 replies; 3+ messages in thread
From: H.J. Lu @ 2021-07-31 12:42 UTC (permalink / raw)
To: Andreas Schwab; +Cc: H.J. Lu via Libc-alpha
On Fri, Jul 30, 2021 at 10:40 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
>
> On Jul 30 2021, H.J. Lu via Libc-alpha wrote:
>
> > Since GCC 4.6, the main function is placed in .text.startup section.
>
> Not generally.
>
> > Place ENTRY_POINT in .text.startup section fixes [BZ #28153].
>
> The linker places .text.unlikely and .text.exit before .text.startup.
We can put it in .text.unlikely section.
> Andreas.
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
--
H.J.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-07-31 4:22 [PATCH] Place ENTRY_POINT in .text.startup section [BZ #28153] H.J. Lu
2021-07-31 5:40 ` Andreas Schwab
2021-07-31 12:42 ` H.J. Lu
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